The project will design, implement, and evaluate a Social Security program in the state of Yucatan, Mexico with a randomized control trial methodology. The Social Security program will be phased in over a three year period, allowing for the judicious choice of treatment and control groups and baseline and follow-up measurements. The proposed program will include both a monthly cash transfer and a health component. In order to ascertain the optimal design of the program, the effects of each component of the program on the health and well-being of elderly recipients will be evaluated. Program parameters will be varied experimentally and their effects will be evaluated. Interventions include anemia treatments, providing health care access, means testing, frequency of benefit payments, and variation of age eligibility rules. A broad spectrum of outcomes will be considered, including health behaviors, dietary practices, physical performance measures, functionality, and selected biomarkers; health care utilization and expenses; cognitive capabilities; social contacts, consumption, financial transfers, mental health, assets and income. The experimental set-up will be used to shed light on key behavioral parameters, such as the effect of financial resources on health and nutrition and on health care utilization; the short and long term relation between financial resources and subjective well-being; the importance of hyperbolic discounting; household risk management strategies and consumption smoothing in response to health shocks; intrahousehold transfers; the income elasticity of labor supply among the elderly.